Nitrogen FixationNitrogen IsotopesNitrogen CompoundsNitrogen DioxideNitrogen CycleBlood Urea NitrogenComplex MixturesReactive Nitrogen SpeciesNitrogen OxidesPII Nitrogen Regulatory ProteinsCarbonAmmoniaNitratesFertilizersQuaternary Ammonium CompoundsAmino AcidsGlutamate-Ammonia LigaseUreaSoilNitrogen Mustard CompoundsNitrogenaseBiomassSymbiosisMolecular Sequence DataPlant RootsGlutamineBacterial ProteinsDigestionCulture MediaPlant LeavesAcetyleneKineticsHydrogen-Ion ConcentrationOxidation-ReductionPoaceaeGene Expression Regulation, BacterialAnimal FeedPhosphorusAllantoinTemperatureFermentationAmmonium CompoundsNitritesGlutamate SynthaseBacteriaWaterTime FactorsCattleEcosystemRoot Nodules, PlantHeliumCarbon DioxideAmino Acid SequencePhotosynthesisAir PollutantsNitrate ReductaseCyanobacteriaDenitrificationGenes, BacterialBase SequenceMedicago sativaMagnetic Resonance SpectroscopySoybeansMutationModels, BiologicalSoil MicrobiologyRumenOxygenChromatography, High Pressure LiquidGasesEscherichia coliMass SpectrometryStereoisomerismMolecular StructureKetoglutaric AcidsNutritional RequirementsCaseinsBiodegradation, EnvironmentalEnvironmental MonitoringGlutamate DehydrogenaseCarbon IsotopesFabaceaePlantsRhizobiumDietFreezingBody WeightAgricultureEnergy MetabolismSulfurAmino Acids, EssentialGATA Transcription FactorsTreesSinorhizobium melilotiAtmosphereGene Expression Regulation, FungalZea maysNitrous OxidePlant ShootsFeces